>
> Hi yu,
>
> On 12/2/2023 5:22 AM, Yu Zhao wrote:
> > Charan, does the fix previously attached seem acceptable to you? Any
> > additional feedback? Thanks.
>
> First, thanks for taking this patch to upstream.
>
> A comment in code snippet is checking just 'high wmark' pages might
> succeed here but can fail in the immediate kswapd sleep, see
> prepare_kswapd_sleep(). This can show up into the increased
> KSWAPD_HIGH_WMARK_HIT_QUICKLY, thus unnecessary kswapd run time.
> @Jaroslav: Have you observed something like above?
I do not see any unnecessary kswapd run time, on the contrary it is
fixing the kswapd continuous run issue.
>
> So, in downstream, we have something like for zone_watermark_ok():
> unsigned long size = wmark_pages(zone, mark) + MIN_LRU_BATCH << 2;
>
> Hard to convince of this 'MIN_LRU_BATCH << 2' empirical value, may be we
> should atleast use the 'MIN_LRU_BATCH' with the mentioned reasoning, is
> what all I can say for this patch.
>
> + mark = sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING ?
> + WMARK_PROMO : WMARK_HIGH;
> + for (i = 0; i <= sc->reclaim_idx; i++) {
> + struct zone *zone = lruvec_pgdat(lruvec)->node_zones + i;
> + unsigned long size = wmark_pages(zone, mark);
> +
> + if (managed_zone(zone) &&
> + !zone_watermark_ok(zone, sc->order, size, sc->reclaim_idx, 0))
> + return false;
> + }
>
>
> Thanks,
> Charan
--
Jaroslav Pulchart
Sr. Principal SW Engineer
GoodData
